Antioxidants Explained in
Human Terms
I am sure that in most
conversations that go on from day to day, antioxidants feature regularly, yet
many of us really fully understand what antioxidants are and how they work.
This article is put
together to bring the issue of antioxidants down to level of understanding of
every one.
What Are Antioxidants and
How do They Work?
In order to understand how
antioxidants work, we must start at the molecular level…
As you may know, all
matter in the universe is made of atoms.
Atoms are composed of a
core with protons and neutrons, and a bunch of electrons that revolve around
the core.
Here is a simple diagram of
an atom:
The blue balls are
electrons, which carry a negative (-) charge, while the protons (red balls) in
the core carry a positive (+) charge.
When two or more atoms are
linked together, they become what we know as molecules.
The human body is made up
of substances like proteins,
fats and DNA, which are basically just large molecules with dozens, hundreds or
thousands of atoms joined together.
This is an image of a fatty
acid molecule. Each ball represents an atom:
Humans and other organisms
maintain their structure and function by chemical reactions. All the chemical
reactions needed to sustain life are collectively known as metabolism.
In these chemical
reactions, bigger molecules are broken down into smaller molecules, and smaller
molecules are organized into bigger molecules.
In order for a molecule to
be stable, it must contain the right amount of electrons. If the molecule loses
an electron when it isn’t supposed to, it can turn into a free radical.
Free radicals are
unstable, electrically charged molecules in the cells, that can react with
other molecules (like DNA) and damage them.
They can even form chain
reactions, where the molecules they damage also turn into free radicals.
This is where antioxidants
come in… if a molecule loses an electron and turns into a free radical, the
antioxidant molecule steps in and “gives” the free radical an electron,
effectively neutralizing it.
This is how it happens:
This is the mechanism
behind antioxidants. They donate electrons to free radicals, which neutralizes
them and prevents them from causing harm.
Bottom Line: Antioxidants are molecules that fight damage by free
radicals, unstable molecules that can harm cellular structures.
Antioxidants do this by
giving electrons to the free radicals and neutralizing them.
Antioxidants and Free
Radicals Are Both Important
Free
radicals are constantly being formed during metabolism.
Without
antioxidants, they would destroy our bodies very quickly.
However,
it’s important to keep in mind that free radicals also serve important
functions that are essential for our survival
For example,
the body’s immune cells use free radicals to kill bacteria that try to infect
us
As with so
many things in the body, we need a certain balance… we need the right amount of free radicals,
and the right amount of antioxidants to keep them in
check.
When this
balance gets disrupted, things can start to go wrong.
When the
free radicals (pro-oxidants)
outnumber the antioxidants,
this can lead to a state called oxidative stress.
During
oxidative stress, important molecules in the body can become severely damaged…
sometimes even leading to cell death.
Several
stress factors and lifestyle habits are known to promote excessive free radical
formation and oxidative stress:
Air
pollution.
Cigarette
smoke.
Alcohol
intake.
Toxins.
High blood
sugar levels
Consuming
large amounts of polyunsaturated fatty acids
Radiation,
including excessive sunbathing.
Infections
by bacteria, fungi or viruses.
Excessive
intake of iron, magnesium, copper, or zinc
Too little
oxygen in the body
Too much oxygen in the body.
Intense and
prolonged exercise, which causes tissue damage
Excessive
intake of antioxidants, such as vitamins C and E
Antioxidant
deficiency
Prolonged
oxidative stress leads to increased risk of negative health outcomes, such as
cardiovascular disease and certain types of cancer. It is also thought to
contribute to the aging process.
Bottom line: The body needs a certain balance between
free radicals and antioxidants. When this balance is disrupted, it can lead to
oxidative stress, which can cause all sorts of negative effects.
Antioxidants
Are Essential for Life and Are Found in All Sorts of Foods
Antioxidants
are essential for the survival of all living things.
The human
body even generates its own antioxidants, such as the cellular antioxidant glutathione.
Plants and
animals, and all other forms of life, have their own defenses against free radicals
and the oxidative damage caused by them.
Therefore,
antioxidants are found in pretty much all foods of plant and animal origin.
Getting
antioxidants from foods is
important. In fact, our life depends on the intake of certain antioxidants –
namely, vitamin C and vitamin E.
The health
benefits associated with a diet rich in plants is, at least partially, due to
the wide diversity of antioxidants they provide.
Meat
products and fish also contain antioxidants, but in smaller amounts compared to
fruits and vegetables. Berries are a particularly good source.
Then there
are plenty of other good sources of antioxidants… including green tea, coffee and dark chocolate.
According to
some studies, coffee is
actually the single biggest source of antioxidants in the Western diet, but
this is partly because the “average” individual doesn’t eat that many
antioxidant-rich foods.
Antioxidants
can increase the shelf life of both natural and processed food products.
Therefore, they are frequently used as food additives.
For
instance, vitamin C is often added to processed foods to act as a preservative.
Bottom line: Our diet is an essential source of
antioxidants. They are naturally found in foods of both plant and animal
origin, especially in vegetables, fruits and beverages like coffee and tea.
Types of
Dietary Antioxidants
There is a
huge variety of different antioxidants found in foods.
They can be
broadly categorized into two groups, water-soluble and fat-soluble
antioxidants.
Water-soluble
antioxidants perform their actions in the fluid inside and outside cells,
whereas fat-soluble antioxidants act primarily in cell membranes.
Here is a
list of a few important dietary antioxidants:
Vitamin C: One of the most important water-soluble
antioxidants and an essential dietary nutrient.
Vitamin E: The main fat-soluble antioxidant that
plays a critical role in protecting cell membranes against oxidative damage.
Flavonoids: A large group of antioxidants found in
plant foods. They have many beneficial health effects.
Many
substances that happen to be antioxidants can also have other important
functions.
Notable examples
include curcuminoids in turmeric and
oleocanthal in extra virgin olive oil.
These
substances function as antioxidants, but they also have potent
anti-inflammatory activity).
Bottom Line: There are many different types of
antioxidants in the diet, including vitamins C and E, as well as flavonoids.
These substances can serve various other functions that are not related to the
antioxidant activity.
Should You
Take Antioxidant Supplements?
Dietary
intake of antioxidants is essential for optimal health.
However, more is not always better.
Excessive
intake of isolated antioxidants can have toxic effects and may even promote
rather than prevent oxidative damage.
In fact,
some studies have shown that high doses of antioxidants increase the risk of death.
Therefore,
you should avoid high-dose antioxidant supplementation.
In addition,
studies show that foods reduce oxidative damage more than supplements.
For example, a
study using blood orange juice showed that it had significantly greater
antioxidant power than a drink with sugar water that contained the same amount
of Vitamin C.
The truth is…
real foods have hundreds (if not thousands) of
different nutrients that work synergistically.
Taking just
one or two isolated nutrients won’t have the same beneficial effects.
The best
(and healthiest) strategy to ensure adequate intake of antioxidants, is a diet
rich in various vegetables and fruit, along with other healthy dietary habits.
However,
low-dose supplementation, such as in multivitamin tablets, may be beneficial if
you are deficient in certain nutrients or unable to follow a healthy diet.
Take Home
Message
Adequate intake
of antioxidants is an essential part of a healthy diet… but getting too much of
isolated antioxidants (via supplements) can in some cases be harmful.
At the end
of the day, the best way to ensure that you get the right amount of antioxidants, is to eat a
real food based diet that includes plenty of healthy fruits and vegetables.
Source: Authority Nutrition
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